Elon Musk may be looking for things to take his mind off the troubles at Tesla or the next SpaceX launch.

The billionaire has shared a time-lapse video of a tunnel under Los Angeles created by his other pet project: The Boring Company.

Effectively a new type of subway, Musk captioned his video with the fact that the first test rides will be given away for free.

As well as a tunnel in LA, The Boring Company is also planning to build underneath Washington DC and Chicago - providing regulators approve. It already has a two mile test track underneath Spacex's headquarters in Hawthorne, California.